"Season two is all about [Oliver] going from vigilante to being a hero," said Guggenheim.

"Especially in comics, we tend to use those words interchangeably, but season two really spells out the difference between what it means to be a vigilante and what it means to be a hero.

"That's something we grab by the throat and don't let go of starting in episode one of season two."

Arrow's first season finale saw Oliver's best friend Tommy (Colin Donnell) sacrifice his life to save Laurel (Katie Cassidy), with Guggenheim promising that the character's death will "echo throughout season two".

"It really was a stone thrown in the pond of Arrow and the ripples continue to extend," he promised.

"We didn't kill off Tommy just to end the season with a bang. We did it for all the long-term effects it will have on Oliver and the rest of the cast."

Arrow will return to The CW this fall, paired with The Tomorrow People on Wednesday nights. The series airs on Sky1 in the UK.